Method and apparatus for automatically evacuating conduits



T. H. CLINE Oct. 4, 1966 METHOD AND APPARATUS FOR AUTOMATICALLY EVACUATING CONDUITS Filed Feb. 19, 1965 jizyizfar $2.322 m 1mm Iw NZU QMFEMQQ 25m w fimw 102261 2. M dgg United States Patent 3,276,628 METHOD AND APPARATUS FOR AUTOMATI- CALLY EVACUATING CONDUITS Truman H. Cline, Mansfield, Ohio, assignor of one-half to Lucille E. Cline Filed Feb. 19, 1965-, Ser. No. 433,864 Claims. (Cl. 222-1) My invention relates to automatic evacuation of conduits and more particularly is applicable to coin-controlled car wash apparatus wherein an open stall, or bank of stalls, available for public accommodation, is provided, each stall having a coin-controlled car washing facility. A coin in a slot renders available a portable hose and nozzle for projecting onto an automobile, for a given length of time, a supply of wash water containing detergent. I

Such facilities are open to certain objections, one of the most serious of which is the risk of damage from freezing in cold climates.

A particular object of my invention is to provide, in apparatus of the type referred to, automatic means for evacuating the aqueous fluid left therein at the conclusion of a washing operation.

More particularly, my invention contemplates, in combination with coin-controlled washing equipment of the type referred to, a source of air under pressure which is normally held in reserve and is automatically released promptly upon conclusion of said washing'operation, and a method of accomplishing said functions.

A further object of my invention is to provide equipment of the type referred to which is simple, inexpensive and foolproof in operation.

Various other objects and advantages will become apparent as the description proceeds.

Referring now to the drawing forming a part of the specifications and illustrating a preferred embodiment of my invention,

FIG. 1 is a schematic elevational view showing a bank of wash stands or stalls for automobiles to which my invention is applied;

FIG. 2 is a more or less schematic view, partly in section, of equipment applying my invention to a series of coin-operated Wash stands, and

FIG. 3 is an electrical wiring diagram for the air supply means forming part of my invention.

FIG. 1 shows schematically a series of open stalls A, B, C and D for public accommodation for manually washing an automobile. A service compartment E, preferably centrally located, is provided for housing certain equipment utilized in accordance with my invention and shown in some detail in FIG. 2.

The stalls are provided with discharge conduits a, 10b, 10c and 10d, such as a hose or the like, leading from a suitable central source of supply of washing fluid such as water containing detergent or soap, and provided with a portable nozzle '15 of the usual or any suitable type for directing a jet of washing fluid onto the surface of a car, and may be provided with a squeegee or other suitable cleaning device.

Each conduit, such as 100:, is connected to a source of hot water (not shown), with or without detergent, through a supply conduit in which is interposed for each stall a check valve 22. On the downstream side of check valve 22 is a T coupling 25 permitting introduction of compressed air into conduit 10a from conduit 28 at the appropriate time.

Compressed air is conveyed to each of the respective washing conduits 10a, etc., via a series of conduits 28 leading from a compressed air storage tank 30 via a manifold 33, a suitable valve such as a standard globe 3,276,628 Patented Oct. 4, 1966 "ice valve '35 being interposed between tank 30 and mani fold 33, said valve being normally open.

Disposed in conduit 28 between manifold 33 and each of the air conduits 2 8 is a suitable solenoid valve 38, which may be of a' type known in the art. In each conduit 28 between fitting 2-5 and solenoid valve 68 is a high pressure check valve 40 and downstream thereof a pressure actuated electrical switch 42.

It will be understood that all of said parts may be standard in character.

The operation of the equipment just described is as follows: Upon insertion of a coin in the meter (not shown) in one of the stalls, master switch S (FIG. 3) is closed, starting an electrical motor. A hydraulic pump P thus will be actuated, building up water pressure to approximately 450 to 500 pounds per square inch. When the operator opens the wash nozzle, check valve 22 in his line, say 1011, will be opened and high pressure valve 40 will be closed, and at the same time pressure switch 42 will be closed as a result of said hydraulic pressure, energizing and opening solenoid air valve 38 for the appropriate air conduit.

Compressed air thereupon will be permitted to flow from reservoir 30 into the appropriate air line 28, where it will remain static under a pressure of about 50-70 pounds per square inch, high pressure check valve 40 being retained in closed position by reason of the higher fluid pressure against it from the pump P.

After the expiration of a given length of time, as determined by the coin meter (not shown), switch S will automatically be opened, stopping the motor and pump P, resulting in a pressure drop in liquid line 10a and permitting pressure switch 42 -to open automatically, closing solenoid air valve '38 for the particular conduit.

After the hydraulic pressure in the liquid line has dropped below the air pressure in that line, high pressure check valve 40 will open automatically, and the air pressure will thereupon flow into the liquid conduit, closing check valve 22 and thus preventing backfiow of air into liquid line 20. At the same time, the charge of air under pressure in line 28 will expel all liquid from the entire liquid conduit 10a and the line will remain clear until the cycle is repeated by insertion of another coin in the meter. Thus, all possibility of freezing in the conduit will be obviated.

Referring to the wiring diagram shown in FIG. 3, conductors V and V are connected to a suitable source of line voltage. An automatic pressure switch S will serve to maintain the air within air reservoir 30 at the desired pressure by means of a suitable motor-compressor 4 5. A transformer T will serve to convert the line voltage to a suitable low voltage (say 12 or 24- volts) to actuate the solenoid-controlled air valves 38.

Connected in series with each solenoid 38 is a fluidpressure switch 42, arranged between check valve and discharge line (FIG. 2), as described above.

It may be noted here that I do not consider it essential to provide a transformer in the line, as indicated by reference character T, inasmuch as the solenoids and fluid-pressure switches may be operated on the line voltage. However, for purposes of safety, reliability and economy it is desirable to reduce the line voltage, as indicated above.

Various changes coming within the spirit of my invention may suggest themselves to those skilled in the art; hence, I do not wish to be limited to the specific embodiment shown and described or uses mentioned, but intend the same to be merely exemplary, the scope of my invention being limited only by the appended claims.

I claim:

:1. In a system for periodically supplying a discharge of aqueous fluid, including a liquid supply, pump and a discharge conduit, means for clearing said discharge of aqueous liquid after each supply cycle, comprising (a) a source of air under pressure substantially lower than the normal liquid pressure in said conduit,

(b) an air conduit connecting said source to said discharge conduit,

(c) valve means controlling the flow of air from said source to said air conduit,

((1) means actuated by the liquid pressure in said discharge conduit for opening said valve means when liquid is flowing in said discharge conduit and closing said valve means when said liquid is static,

(e) a check valve permitting passage of air from said source to said discharge conduit only when liquid in the latter is static and is closed by liquid pressure when liquid is flowing through said discharge conduit, and

(f) a check valve normally open to permit flow of liquid through said discharge conduit and closed by air pressure from said source after liquid flow has discontinued.

2. In a system for periodically supplying a discharge of liquid, including a pump and a discharge conduit, means for clearing said discharge of liquid after each supply cycle, comprising (a) a source of gas under pressure substantially lower than the normal liquid pressure in said conduit,

(b) a gas conduit connecting said source to said discharge conduit,

(c) a check valve permitting passage of gas from said source to said discharge conduit only when liquid in the latter is static and is closed by liquid pressure when liquid is flowing through said discharge conduit, and

(d) a check valve normally open to permit flow of liquid through said discharge conduit and closed by gas pressure from said source after liquid flow has discontinued, whereby, when flow of liquid is termi nated in said discharge conduit, gas will automatically flow through said discharge conduit to clear the latter of liquid.

3. In a system as in claim 1, electrical means for actuating said air valve, including a pressure switch and a solenoid controlled thereby for motivating said valve.

4. A method of clearing liquid from a conduit connected to a source of liquid under high pressure and to a source of gas under relatively low pressure, comprising (a) restraining the flow of gas into said conduit by means controlled by the liquid pressure in said conduit when liquid is flowing therein,

(b) stopping the flow of said liquid, and

(c) introducing gas from its source into said conduit by means controlled by the differential between the pressure of gas in said source and the reduced pressure in said conduit to discharge liquid remaining in said conduit.

5. A method as in claim 4, wherein (a) a charge of approximately the amount of gas under pressure to clear said conduit of liquid is established from a gas reservoir by means controlled by the liquid pressure in said conduit when liquid is flowing therethrough,

(b) the supply of gas from said reservoir is restricted, by means controlled by the drop in pressure within said conduit, to an amount approximately suflicient to clear said conduit of liquid, and

(c) 'backflow of gas into said liquid source is prevented by means actuated by pressure of said gas charge.

References Cited by the Examiner UNITED STATES PATENTS 1,962,027 6/1934 Miner 137-l13 2,580,199 12/1951 Schmid 137-112X ROBERT B. REEVES, Primary Examiner. S. H. TOLLBERG, Assistant Examiner. 

4. A METHOD OF CLEARING LIQUID FROM A CONDUIT CONNECTED TO A SOURCE OF LIQUID UNDER HIGH PRESSURE AND TO A SOURCE OF GAS UNDER RELATIVELY LOW PRESSURE, COMPRISING (A) RESTRAINING THE FLOW OF GAS INTO SAID CONDUIT BY MEANS CONTROLLED BY THE LIQUID PRESSURE IN SAID CONDUIT WHEN LIQUID IS FLOWING THEREIN, (B) STOPPING THE FLOW OF SAID LIQUID, AND (C) INTRODUCING GAS FROM ITS SOURCE INTO SAID CONDUIT BY MEANS CONTROLLED BY THE DIFFERENTIAL BETWEEN THE PRESSURE OF GAS IN SAID SOURCE AND THE REDUCED PRESSURE IN SAID CONDUIT TO DISCHARGE LIQUID REMAINING IN SAID CONDUIT. 